Method of treating plastered ceilings and walls



S. L. MORTENSEN METHOD OF TREATING PLASTERED CEILINGS AND WALLS Filed Aug. 1. 1923 Nov. 17, 1925- 1,561,520

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by 771M.W C0W 34x4 Patented Nov. 17,- 1925.

SOFUS L. MORTENSEN, OF BOSTON, MASSACHUSETTS.

METHOD OF TREATING PLASTERED CEILINGS AND WALLS.

Application filed August .1, 1923. Serial No. 655,020.

To all whom it may concern:

Be it known that I, Sores L. MORTENSEN,

a citizen of the United States, residing at Boston, county of Suffolk, and State of 1 'Massachusetts, have invented a certain new and useful Improvement in Methods of Treating Plastered Ceilings and Walls, of which the folowing is a specification, reference being had therein to the accompanying drawings.

In old churches and other buildings, where the walls and ceilings have been finished With plaster laid on wooden laths, it is frequently found that after a'period of ance of dark streaks, the dark streaks being over the spaces between the laths. The discoloration is caused by the air currents driving the dust against the ceiling. The porous spaces between the laths hold the dust more than the spaces which come against the timbers and laths. This occurs even when the plaster surface is painted over. The object of my invention is to provide a method of treating the surfaces with plaster, in such manner as to prevent the formation of these dark streaks when such method is applied to new plastered surfaces, and to conceal the dark streaks and prevent the formation of new dark streaks when the method is applied to old buildings in which the dark streakshave already appeared.

The invention will be fully understood from the following description when taken in connection with the accompanying drawings, and the novel features thereof will be pointed out and clearly defined in the claims at the close of this specification.

In the drawings:

Fig. 1 is a fragmentary view showing in plan a portion of the plastered ceiling.

Fig. 2 is'a plan view showing the ceiling after the sheets of tinfoil have been adhesively applied thereto, a corner of one of the sheets being turned to the left.

Fig. 3 is a sectional view showing the ceiling after it has been treated in accord-- ance with my invention. Fig. 4 is a sectional view on an enlarged scale of the portion of the finished ceiling. Referring now to the drawings, there is shown at 1 a plastered wall or ceiling laid on laths 2 which are nailed onto the timbers of furring 3. In the usual method of applying wooden lathing, the laths are not years the work is disfigured by the appearlaid close. together but are separated by spaced 4. With the usual method of finishing there will appear on the surface of the plaster opposite the spaces between the laths dark streaks 6 caused by the dust in the manner previously described. In carrying out my invention, I cover the plastered ceiling with sheets of metal foil 7, care fully and smoothly laid so that there will be no joints between the different sheets. Any suitable kind of foil may be employed, but tinfoil is preferred on account of its cheapness. In order to avoid any possible open joints between the sheets of foil, the sheets are laid so as to overlap, as shown by the dotted lines 8 and full lines 12.

The sheets of foil should be firmly at tached to the surface of the plaster throughout. This is preferably done by means of adhesive, as shown at 9, and the preferred adhesive is shellac.

The outer surface of the foil is finished by painting but in order to prepare the foil for receiving the paint the foil is prefer ably first coated on its outer face with shellac as shown at 10, because the paint will not readily adhere directly to the surface of the tinfoil; then the coat of paint 11 is applied to the shella'cked surface.

The metal foil is impervious to air and I find in practice that when the ceiling is treated as hereinabove described,-the formation of dark streaks will be entirely prevented on new ceilings, and when old cellings are thus treated the old discoloration will be concealed and further discoloration from the same cause will be prevented.

What I claim is: 1

1. The method of treating plastered walls and ceilings having plaster laid on laths which have air spaces between them, said method consisting of applying an adhesive to the plastered surface, and placing metal foil upon said adhesive.

2. The method of treating plastered walls and ceilings having plaster laid on laths which have air spaces between them, said method consisting of applying an adhesive to the plastered surface, placing metal foil upon said adhesive, and appl in a coat of paint to the outer surface of t e oil.

3. The method of treating plastered walls and ceilings having plaster laid on laths which have air spac between them, said method consisting of ippl ing anadhesive to the plastered surface, p acmg metal foil upon said adhesive, applying a coat of shellac to the outer face of the foil, and apply- 'ing a coat of paint to the shellacked surface.

4. The method of treating plastered walls and ceilings having plaster laid on laths Which have air spaces between them, said method consisting of applying an adhesive to the lastered surface, placing tin foil upon said adhesive, applying a coat of shellac to the outer face of the tin foil and applying a coat of paint to the shellacked surface.

5. The method of treating plastered walls and ceilings having plaster laid on laths which have air spaces between them, said method consisting of adhesively securing sheets of metal foil to the surface of the plaster by means of shellac, applying a coat of shellac to the outer face of the foil and applying a coat of paint to said shellacked surface.

6. In combination with a wall or ceiling memao having plaster laid upon laths which are space apart from each other in such man:

' overlay of metal foil adhesively secured to the outer face of the plaster, and acoat of shellac on the outer face of the metal foil.

8. In combination with a wall or ceiling havin plaster laid upon laths which are space apart from each other in'such manner as to leave air spaces between them. an overlay of metal foil adhesively securer. to the outer face of the plaster, a coat of shellac on the outer face of the metal foil, and a coat of paint on said shellacked surface.

In testlmony whereof, I affix mysignature.

' SOFUS L. MORTENSEN. 

